The present invention relates to a lid for an accumulator battery, comprising a substantially flat main closure element for closing a container of the battery, in which closure element a plurality of holes is formed to afford access to the interior of the battery container, a secondary closure element which is mounted on the main element and in which there is a plurality of plugs that are fitted in the holes of the main element of the lid, and at least one duct which is formed in at least one of the main and secondary elements, is in flow communication with the holes, and is provided for the discharge of the gases that are generated inside the battery container.